ADJUSTABLE CUTTING TOOL FOR A PEELING OPERATION

Abstract: The present invention provides a tool for bar peeling comprising a rotatable cutter head (11) with circumferentially spaced toolholders (12), each said holder being provided with an adjustment device comprising a setting unit (18) provided with a protrusion (19) having a recess (25), the bottom of which is inclined to match a corresponding wedge (29) to be received therein, said holder (12) and setting unit (18) being longitudinally displaceable upon actuating a lateral movement of said wedge (29) in said recess (25), thus accomplishing radial adjustment of the insert (13) on said holder in relation to a workpiece (10).

Description: ADJUSTABLE CUTTING TOOL FOR A PEELING OPERATION The present invention relates to a cutting tool for turning operations. More specifically the invention relates to a cutting tool with an improved radial adjustment device for a bar peeling operation performed on solid or hollow bars formed of stainless steel or other heat resistant materials. The cutting tool comprises a holder equipped with one or several cutting inserts including an upper chip face, an opposite bottom face and a clearance face located therebetween, whereby the intersection of the chip face and the clearance face forms a cutting edge. Each insert is made of cemented carbide or similar wear resistant material. Bar peeling as a metalworking operation means that an elongated bar is axially displaced through a central hole of a rotary cutter head. The cutter head is provided with several tools which remove from the bar a thin layer of millscale, surface cracks, etc., that results from the hot rolling of such bars or tubes . In order to achieve the best results regarding tolerances and surface finish, two different types of inserts, i.e., roughing and finishing inserts, are usually combined in the same holder. After the mounting of the holder into its location in the rotary cutter head it is desirable to be able to make a fine adjustment of the exact radial position of each cutting insert (normally 4) . This adjustment is usually accomplished by grinding the insert after it has been put into its location in the holder. The disadvantage of this method is that by grinding the insert also means taking away a surface layer that normally has been deposited on the surface of the insert, normally by CVD-technique, for the purpose of increasing the lifetime of the insert. Further, it is never possible to reach exactly the same amount of grinding on each of these four inserts which makes the tool less precisive. According to an alternative method precision is improved by arranging spacer plates in the toolholder that needs adjustment. Such procedure, however, is time consuming and gives no precise results. In EP-A-131 784 there is disclosed a device for radial adjustment that is mounted into the holder which carries the cutting insert . This device comprises an adjustable wedge element one surface of which is in direct surface contact with a separate adjusting element. There is a large risk of vibrations with such tool, partly because the adjusting element is insufficiently dimensioned, and partly because the use of a single clamping screw is insufficient and is likely to cause a play in the tool which will lead to undesireable vibrations. In view thereof, it is a purpose of this invention to provide a device in the tool holder that can be easily handled and enables radial adjustment of the inserts with large precision and which can be mounted in the holder and requires a limited space. This improved device comprises a sealed wedge device protected against dirt that can be actuated by a setting screw from its opposite sides of the holder, and which also is actuated by a clamping screw that is acting from the rear end of the tool holder. This makes it possible to accomplish fine adjustment by simple means without having to use separate fixtures in connection with the fine adjustment of the cutting insert. These and other objects of the invention are achieved by a cutting tool having those specific features that are defined in the enclosed patent claims. The objects and advantages of the invention will become more apparent from the following detailed description of a preferred embodiment thereof in connection with the accompanying drawings in which: Fig 1 is a perspective view of a conventional cutting tool for bar peeling, Fig 2 is a front view of four toolholders of the invention which are oriented in same manner as shown in Fig 1, Fig 3 is a side view of the toolholder arranged for the machining of a bar in accordance with the invention, Fig 4 is a plan view of the toolholder in Fig 3, Fig 5 is an end view of the toolholder in Figs 3-4, Fig 6 is a side view of an adjusting device at the end of the toolholder, Fig 7 is another side view of the adjusting device in Fig 6, Fig 8 is an end view of the adjusting device in Fig 6, and Fig 9 is a side view of a wedge element that is one portion of the device of the invention. In Fig 1 there is a cylindrical bar 10, which is intended to be subject of a bar peeling operation by a rotary cutter head 11 equipped with a plurality of radially extending holder shafts 12, each of which is carrying one or several cutting inserts 13 of cemented carbide or similar hard and wear resistant material . As appears from Fig 2-4 each holder 12 is at one end provided with a pocket 14 for the receipt of a releasably attached cutting insert 13. The holder 12 is at its opposite end provided with an end surface 15 that is oriented perpendicular to the longitudinal direction of the holder 12 and there is a recess 16 in said holder which extends to said end surface 15. The holder 12 is T-shaped in cross section as a consequence of the provision of longitudinally extending ridges 17 along two opposite side surfaces of said holder against which correspondingly designed guides shall be in contact when mounting said holder in a corresponding rotary bar peeling cutter head. An adjusting device 18 is provided having a central protrusion 19, said device having a laterally extending flat surface 20 intended to abut against a corresponding flat end surface 15 of said holder whilst said protrusion 19 is received in said recess 16. The outer mantle surface 21 of said adjusting device 18 is convexly rounded to match a correspondingly curved

Claims: Claims 1. A tool for bar peeling comprising a rotatable cutter head (11) equipped with a plurality of distantly provided holders (12) each of which is carrying one or several inserts (13) of wear resistant material, each said holder being provided with an adjustment device including a wedge element (29) in order to enable adjustment of the position of the insert, c h a r a c t e r i z e d in that the adjustment device includes a setting unit (18) with a centrally provided protrusion (19) which is received in a recess (16) that extends in the longitudinal direction of the holder (12) said wedge element (29) being received centrally in a recess (25) of said protrusion (19) , whereby pressure means (31, 32) are provided in said holder, each of which being engageable with one of its end surfaces in surface abutment with said wedge so that said wedge upon lateral movement causes a movement of said holder (12) and said insert (13) in the longitudinal direction of said holder thus adjusting the radial position of said insert (13) in relation to a workpiece (10) . 2. A tool as defined in claim 1, c h a r a c t e r i z e d in that the rear end surface of the holder is a flat surface (15) oriented perpendicular from the longitudinal direction of the holder, said flat surface (15) being intended for surface abutment with a corresponding flat surface (20) of said setting unit (18) . 3. A tool as defined in claim 1, c h a r a c t e r i z e d in that the protrusion (19) has a rectangular cross section and that a recess (25) extends laterally through said protrusion, said recess being confined by two substantially flat extensions (26, 27) , said recess (25) having a flat bottom surface (28) that is inclined from the longitudinal direction of said protrusion against which said wedge (29) is intended to be in surface contact . 4. A tool as defined in claim 1, c h a r a c t e r i z e d in that the wedge (29) has a smaller cross section than said protrusion and is provided with a central bore (30) for the receipt of a screw (23) arranged for releasably securing said setting unit (18) in said holder (12) , said bore (30) having an elongated cross section so as to enable its lateral adjustability. 5. A tool as defined in claim 4, c h a r a c t e r i z e d in that said pressure means (31, 32) is in the form of two linearly oriented screws each of which is threadably engaged in the holder, one on each side of said protrusion (19) .

Inventors: DAHLLOEF YNGVE, HANSSON SOELVE, DAHLLOEF, YNGVE, HANSSON, SOELVE
Applicants: SANDVIK AB
Application year: 1994
Main classification: B23B5
IPC codes: B23B5, B23B29